HP emphasised that the software can be easily removed.

Customers have complained that the software severely slows down their systems Justin Sullivan/Getty Images

HP has been accused of stealthily installing spyware on its PCs and laptops without users' consent as part of a Windows update. The software, first identified on 15 November, is an updated version of the HP Touchpoint Manager solution called "HP Touchpoint Analytics Service."

The Analytics Client installs without asking for user permission and "harvests telemetry information" that is used by HP Touchpoint's analytical services. According to its official description, the program provides users with "the tools you need to ensure all your managed devices' security -- and brings you greater peace of mind".

The service reportedly collects data every day and sends it over to HP's licensed cloud-based Devices-as-a-Service (DaaS) services.

However, numerous users on Reddit and HP's own customer forum have confirmed the installation of the software on their systems and reported that it severely slows down their devices. Computer World pulled together some of the numerous complaints and concerns from users.

"It's been making my computer work so hard I can hear it like cranking away and the light in the back of my computer is flashing rapidly in-tune with the cranking. In Task Manager I can see it starting and stopping numerous applications," one complaint on the HP support site reads. "I've been able to use my computer while it's doing all of that, but I don't want to use my computer because I fear all that activity plus me will cause my computer to shut down.

"I'm assuming it was installed in the background as an update to HP support or framework. However it happened I don't appreciate it's sneaky takeover of my computer's system resources."

One user on HP's forums said: "I understand that it hoovers all sorts of telemetry data - and I am not willing to share too much of it really, definitely not without my knowledge."

It is not clear why HP Touchpoint is quietly being rolled out and installed on Windows PCs without users' consent or awareness.

In response to the backlash, HP said in a statement: "HP Touchpoint Analytics is a service we have offered since 2014 as part of HP Support Assistant. It anonymously collects diagnostic information about hardware performance. No data is shared with HP unless access is expressly granted. Customers can opt-out or uninstall the service at any time.

"HP Touchpoint Analytics was recently updated and there were no changes to privacy settings as part of this update. We take customer privacy very seriously and act in accordance with a strict policy."

IBTimes UK has reached out to HP for comment and clarification regarding the service.